[SECURITY ADVISORY] curl case insensitive password comparison

[Daniel Stenberg <daniel () haxx se>]

case insensitive password comparison
====================================

Project cURL Security Advisory, November 2, 2016 -
[Permalink](https://curl.haxx.se/docs/adv_20161102B.html)

VULNERABILITY
-------------

When re-using a connection, curl was doing case insensitive comparisons of
user name and password with the existing connections.

This means that if an unused connection with proper credentials exists for a
protocol that has connection-scoped credentials, an attacker can cause that
connection to be reused if s/he knows the case-insensitive version of the
correct password.

We are not aware of any exploit of this flaw.

INFO
----

The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2016-8616 to this issue.

AFFECTED VERSIONS
-----------------

This flaw exists in the following curl versions.

- Affected versions: curl 7.7 to and including 7.50.3
- Not affected versions: curl < 7.7 and curl >= 7.51.0

libcurl is used by many applications, but not always advertised as such!

THE SOLUTION
------------

In version 7.51.0, these functions will deny negative string lengths from
being used.

A [patch for CVE-2016-8616](https://curl.haxx.se/CVE-2016-8616.patch) is
available.

RECOMMENDATIONS
---------------

We suggest you take one of the following actions immediately, in order of
preference:

 A - Upgrade curl and libcurl to version 7.51.0

 B - Apply the patch to your version and rebuild

TIME LINE
---------

It was first reported to the curl project on September 23 by Cure53.

We contacted distros@openwall on October 19.

curl 7.51.0 was released on November 2 2016, coordinated with the publication
of this advisory.

CREDITS
-------

This vulnerability was found during a Secure Open Source audit performed by
Cure53.

--

 / daniel.haxx.se